30G-29 |
Preparation of a marmalade-type product with osmotic-dehydrated pineapple chunks |
M. MATA1, M. Cabral1, B. Tovar1, and H. S. Garcia2. (1) Lab. de Investigación en Alimentos, Instituto Tecnológico de Tepic, Av. Tecnologico # 2595, Tepic, Nay., 63175, Mexico, (2) UNIDA, Instituto Tecnologico de Veracruz, M.A. de Quevedo # 2779, Col. Formando Hogar, Veracruz, Ver., 91897, Mexico Traditional fruit conserves require high sugar (as soluble solids) concentrations to reduce water activity. Evaporation is achieved by heating but as a result, sensory qualities are lost, mainly in terms of color and typical fruit flavor. Osmotic dehydration consists of immersion of food pieces into concentrated solute solutions. While moisture is lost, solids are absorbed by the foodstuff and some flavor and color components migrate to the osmotic solution. In the present work we report the preparation of a marmalade-type product using the residual syrup from osmotic dehydration and pineapple chunks osmotically dehydrated. A statistical fractional factorial design (26-3) was employed to study six process variables: temperature of osmotic dehydration, treatment time, gel-setting temperature, syrup concentration, osmotic pressure and pineapple chunk size. Sensory evaluation was employed to select the best set of treatments. The best formulation was used to prepare enough product to conduct storage tests for up to 3 months, during which time compositional analyses as well as microbial populations were monitored. Results obtained from the statistical design indicated that osmotic treatment of pineapple chunks can be used to eliminate moisture from the fruit and additionally, utilize the residual syrup to produce a gel with pectin. Better results were obtained with fruit chunks 3x3x0.7 cm, 65 °Bx sucrose syrup at 25 °C and 21 mbar vacuum for 2 h. According to compositional and sensory analyses the product was stable for at least 3 months at ambient temperature, and retained a typical pineapple color and flavor The proposed method provides a practical and inexpensive way to use tropical fruits, specially those whose sensory qualities are heat labile.
Session 30G, Fruit & Vegetable Product: Processed Fruits and Vegetables
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